Artykris, you enter the actual focal length (which is always 50mm for a 50mm lens, irrespective of whether it's on an APS sensor or full 35mm frame). So, you get 0.25m for 50mm/f1.4@3m on 35mm, and 0.2m for the *ist-D (using a circle of confusion value of 0.02mm).

John - you are missing the "circle of confusion" when making your points. The smaller the sensor, the more critical focus is for a given final image size. That's why the DoF reduces for the APS sensor size. The aperture and focal length remain the same, but don't forget you are trying to compare a final print size that's the same for both 35mm and APS size - so the APS has to be "finer". Check the link: http://www.dofmaster.com/digital_coc.html#coccalculator out

When you enter the focal length of a compact camera in the online calculator, you must enter the actual focal length (e.g. 7mm) and not the equivalent-field-of-view-for-35mm

Incidentally, there are plenty of links on that website giving the theory and equations so you can check it out

(I bet these comments will confuse you more )
Matt

Yes, it's different, but it is shallower on an APS image sensor. A subject at 2m using a 50mm/f1.7 lens will give you:
16cm depth on 35mm
11cm depth on the *ist-D

Check out the excellent online calculator at http://www.dofmaster.com/dofjs.html to try it for yourself!!

Matt

I quite agree Especially given the current price!

Correction to my earlier post: the Nikon D2X is not full frame. The Canon 1DS and 1DS mark II are full frame though... but the price !

Matt

Ok so I looked up the prices in the US of full frame Pro DSLRs. $3k won't get you anywhere at all!
Canon 1Ds mark II, full frame costs $8k.
Nikon D2X, full frame costs $5k.

Full frame sensor DSLRs are expensive because the CCDs are so difficult to make. I doubt they'll come down in price much - how many can afford a camera at that price? There's not exactly a huge market. And anyway, the following generations of full frame will pack more pixels, more features, more power and will cost around the same price!

You can wait... and wait... and wait... but to be honest there are plenty of APS sized DSLRs that are being used for professional work (where the photographer gets their main source of income from using the camera).

And in actual fact, the body price is only part of it There's the image editing software (ie Photoshop), then the storage for all those images. I have the *ist-D and have already racked up 14Gb of photos and edits this year, and I am not a pro!

From my non-pro perspective, I have found that the *ist-D has upped my quality no-end. I had to change most of my lenses for better ones, and now when I look back at the Provia slides I took before the quality difference is huge. There's no way I'm going back to film, even to get a bet extra angle of view.

(Climbing off my soap box now! )
Matt

Joshua - just a thought...

If you use your tubes with the lens in "A", but your *ist-D shows "Av --" then there's a contact problem.
I have the same issue with some cheap tubes I have. I just carefully clean the contacts on the tubes (some isopropyl alcohol can help) and they spring to life again.

(Pentax didn't make tubes with electronic contacts. Their "Auto extension tubes" are only auto on old bodies that utilise the mechanical aperture "finger".)

Matt

Dean - glad to help

Have you tried all the shutter speeds?

If you are indoors, and set something like f4 for the aperture, you may need a shutter speed as low as 1/2s. I would suggest you keep the aperture at the lowest value and reducing the shutter speed - eventually the Ev bar should change.

If the Ev bar shows underexposure (-) then that's what you'll get.

Matt

In stock in the US:
http://www.bhphotovideo.com/bnh/controller/home?O=productlist&A=details&...

http://www.parkcameras.com/ in the UK have it listed at £170, but don't say whether it's in stock.

But I really, really, really want the 12-24mm

Matt

For completeness sake:
Here's the link: http://www.pentaximaging.com/footer/news_media_article?ArticleId=6534411

...
Matt

Not yet... nor the SMC-DA 12-24mm.